1. Field of the Invention
The method and apparatus of the present invention relate to the field of heat exchangers, and more particularly to heating, ventilation and air conditioning systems.
2. Description of the Related Art
There are numerous heating, ventilation and air conditioning protocols in use today, for use in industrial, commercial, automotive, and residential applications. Generally, a heating system heats a selected environment by using the heat which is generated when a fuel is combusted in a burner, for heating a liquid or gaseous fluid, and then circulating the heated fluid through a circulatory system including radiators or outlets installed in the selected environment. Likewise, cooling systems including prior art air conditioning systems and heat pumps utilize a refrigerant to extract a heat component from the refrigerant flow on a continuous flow basis. In all of these systems, bidirectional flow relative to a heat exchanger is required to achieve the desired level of heat exchange necessary to heat/cool the selected environment. Specifically, the heat exchanger of the related art includes a first fluid that flows from one chamber to another chamber through bypass or cross-flow conduits, so as to exchange heat with a second fluid flowing in the passages of adjacent, heat-conductive conduits. Such heat exchangers are used as evaporators in coolant fluid circuits in stationary residential, commercial, industrial and automotive applications. Typically, a refrigerant fluid is the first fluid, the second fluid being atmospheric air. Alternatively, the second fluid is typically available in large quantities at substantially low cost, for use in bulk flow heat exchangers, such as water. As is well known in the art, larger industrial heat exchangers are located near large bodies of water, while smaller installations and mobile applications require either a piped-in or on-board supply of water. In any case, however, the prior art relies on relatively high flow through rates of a coolant, such as water, to provide acceptable levels of heat transfer.
Generally, the prior art utilizes plate-type heat exchangers, wherein each plate of the heat exchanger is provided in the form of a fin or shallow tray, and is formed with two apertures serving as the inlet and outlet, respectively, for the first refrigerant fluid. The chamber which is defined between the two plates of any single pair of plates includes an internal partition which gives the fluid flowing in the chamber a generally U-shaped flow path between the inlet aperture and the outlet aperture. This partition is generally formed by sealingly joining together two longitudinal projecting ribs each of which forms part of a respective one of the plates in that pair of plates. The communicating apertures are typically formed in a projecting element or pocket which is arranged at one end of each plate. In addition, the plates are generally joined together at their other end by a base plate which provides spacing between the pair of plates.
When the heat exchanger serves as an evaporator, the refrigerant fluid enters the heat exchanger in the liquid state and leaves the heat exchanger in the vapor state, after having cooled a stream of air by evaporation. Often, water or water-based solutions are used as the second fluid in the so-described systems. Such use is common to HVAC systems both small and large due to a relatively low water costs, as described above, especially in larger systems with long pipe runs and large fluid capacity and heat transfer requirements. However, a water or water-solution based refrigerant/coolant system does not provide optimized, high efficiency operation due primarily to relatively poor heat exchange properties on a specific mass basis. As a result, the necessary plumbing systems mandate massive space and weight requirements.
Accordingly, there is a need for a system and apparatus for overcoming the shortcomings of the related, prior art HVAC systems.
The present invention is a method and apparatus of use of a heat exchanger in an HVAC system utilizing a system refrigerant for heat transfer between a radiator and a heat exchanger, for flowing the refrigerant in heat transfer communication through the heat exchanger. Single or multiple heat exchange loops and flow controllers maintain system balance during operation of the system.